Question

12x + 3y = 9 solve for y​

Answer 1

y = (3) - (4x)

Explanation:

Note: Since there is only one equation given, the value of "y" will not be a fixed value.

Given equation:

• 12x + 3y = 9

Our main goal to solve for "y" is to have the y-variable on one side, and a specific value or variable on the other side (e.g., y = 3 or y = 4x) . Start out by subtracting both sides by 12x. This will isolate the y-variable and it's cooeficient (3).

• ⇒ 12x + 3y = 9
• ⇒ 12x + 3y - 12x = 9 - 12x
• ⇒ 3y = 9 - 12x

Once the y-variable and the cooeificent of the variable have been isolated, we can divide both sides by the cooeficient to isolate the variable.

• ⇒ 3y/3 = (9 - 12x)/3
• ⇒ y = (9 - 12x)/3
• ⇒ y = (9 ÷ 3) - (12x ÷ 3)
• ⇒ y = (3) - (4x)

Therefore, the value of "y" is 3 - 4x.

Answer 2

`\Longrightarrow: \boxed{\sf{y=3-4x}}`

Explanation:

To solve for y, you have to isolate it on one side of the equation.

12x+3y=9

First, you have to subtract by 12x from both sides.

`\Longrightarrow:\sf{12x+3y-12x=9-12x}`

Solve.

`\Longrightarrow:\sf{3y=9-12x}`

Then, you divide by 3 from both sides.

`\Longrightarrow:\sf{(3y)/(3)=(9)/(3)-(12x)/(3)}`

Solve.

`\sf{(9)/(3)-(12x)/(3)}`

`\sf{(9-12x)/(3)}`

Use the distributive property.

`\underline{\text{DISTRIBUTIVE PROPERTY:}}`

⇒A(B+C)=AB+AC

9-12x=3(3-4x)

`\sf{(3\left(3-4x\right))/(3)}`

Divide the numbers from left to right.

3/3=1

3-4x

Then, rewrite the problem down.

`\Longrightarrow: \boxed{\sf{y=3-4x}}`

• Therefore, the correct answer is y=3-4x.

I hope this helps! Let me know if you have any questions.